1. Field of the Invention
The present invention relates to polyimides incorporating repeating units, derived from the dianhydride 5-(2,5-dioxo-tetrahydrofuryl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride and various aromatic diamines.
2. Prior Art
U.S. Pat. Nos. 4,240,914; 4,358,378; 4,385,084 and Pat. No. 4,410,568 disclose asymmetric polyimide gas separation membranes prepared from an aliphatic polyimide material. Said aliphatic polyimide material is compositionally different from that described herein.
U.S. Pat. No. Re 30,351; U.S. Pat. Nos. 3,822,202 and 3,899,309 disclose gas separation membrane materials comprising certain semirigid aromatic polyimides, polyamides and polyesters.
U.S. Pat. No. 4,307,135 discloses the preparation of an asymmetric polyimide membrane from a soluble polyimide.
U.S. Pat. Nos. 4,378,324; 4,460,526; 4,485,056 and 4,512,893 disclose a process for preparing asymmetric polyimide membranes.
U.S. Pat. No. 4,690,873 discloses an aromatic polyimide gas separation membrane material.